Characteristics

Dementors have a twelve feet tall, menacing, human shape that is cloaked in black. They have greyish, scabbed hands that are slimy and glistening (PA5, GF31). Their head is hooded unless they prepare to Kiss somebody. It has no eyes, only thin, grey, scabbed skin stretched over empty sockets. The mouth is a gaping, shapeless hole (PA20). They glide along the ground and exude darkness and coldness (PA5). Only wizards can see Dementors, they are invisible to Muggles and Squibs (PA10, OP8, JKRW). Dementors are blind, but they can feel human emotions and thus human presence. It is therefore impossible to hide from them; even Invisibility Cloaks are useless (PA5). They seem to travel in packs, as they are rarely seen alone.

Dementors embody fear. They dwell in the foulest, darkest places and prosper in times of unhappiness and despair. Soulless themselves (BLC), they feed on the positive emotions of wizards, Squibs and Muggles alike. Whith their slow, rattling breath they suck all hope, peace, and cheerfulness out of their victims and make them relive their worst memories, leaving them nauseated and weak. The effect varies depending on the amount of suffering the victim has experienced. People with many bad memories, for example Harry Potter, can become incapacitated (PA5, PA10). However, animals and Animagi in their animal shape are less affected, because their emotions and thoughts are simpler. Dementors also can track them less easily (PA19).

A Dementor's ultimate weapon is the Dementor's Kiss, in which it takes down its hood and sucks out the soul of the victim, whose body is left alive as an unconscious, empty shell (PA13), a fate that is described as worse than death (GF36).<ref>Some fans believe this is also what Dumbledore speaks of when he says that there are "some things worse than death" during his fight with Voldemort (OP36). However, given the context, it is more likely that Dumbledore means Voldemort's misdeeds and the creation of the Horcruxes.</ref>

Dementors cannot be destroyed. However, their numbers can be limited by fighting the climate of despair and degradation in which they multiply (BLC). The only known way to fight a Dementor is the Patronus Charm.<ref>There seem to be other ways, because Snape disagrees with Harry about the best way to fight Dementors, but we do not know which method Snape prefers (HBP21).</ref> This is a particularly complex charm in which the caster must utter the incantation Expecto Patronum whilst simultaneously concentrating on a happy memory. If the wizard succeeds, this summons a Patronus, an an animal made of silvery vapour that matches the caster's personality. Depending on the strength of the charm, the Patronus can keep a Dementor at bay, chase it off, or even overpower several of the creatures (PA12). Chocolate helps to remedy the aftereffects of a Dementor attack (PA5).

Dementors in the wizarding world

At Azkaban

Before the Second War, Dementors are employed by the Ministry of Magic. Their most important task is to guard Azkaban. They are allowed to feed on the prisoners, robbing them of their strength, hope, and ultimately their sanity (PA6). The continued influence of the Dementors successfully prevents escapes (with the exception of Sirius Black, who is an unregistered Animagus, and Bartemius Crouch, Jr., who exchanges places with his mother). It seems that no humans are constantly present at Azkaban apart from the prisoners; the Dementors do all the jobs from bringing new prisoners to burying them (GF27). They also escort suspects to court trials (GF30). The Ministry's alliance with Dementors is criticised by Albus Dumbledore and his followers, because they doubt that the Ministry is able to control the creatures sufficiently and because they find the cooperation with Dark creatures morally reprehensible (PA4, GF30, GF36, BLC).

Barty Couch, Jr. escapes from Azkaban with the help of Polyjuice Potion. When his parents are granted a deathbed visit, his dying mother exchanges places with him. Because the Dementors are blind and Barty Crouch and his mother feel equally weak to them, they do not notice anything (GF35). When Mrs. Crouch dies, they bury her outside the fortress (GF27).

Sirius Black is one of the best guarded prisoners at Azkaban; Dementors are stationed outside his door day and night (PA10). However, Sirius can lessen their influence by turning into a dog. Furthermore, the knowledge of his innocence—an unhappy thought that the Dementors cannot take away—keeps him sane. When he learns that Peter Pettigrew is at Hogwarts, he slips out of his cell when the Dementors bring his food and swims to the mainland. Confused by his dog shape, the Dementors do not sense him escape (PA19).

Guarding Hogwarts

After Sirius' escape, the Ministry sends Dementors to Hogwarts to guard the school and look for the fugitive. They also patrol the streets of Hogsmeade after nightfall and search the whole village twice (PA10). Albus Dumbledore is not happy about this policy, but he gives his permission (PA4). However, he forbids them to enter the school grounds (PA9). One of the creatures searches the Hogwarts Express on September 1, 1993. It glides through the train, causing panic among the students, until it reaches the last compartment, where Remus Lupin chases it off with the Patronus Charm. Harry Potter relives the memory of his parents' death and loses consciousness. When he awakes, Lupin offers him and the others chocolate. Harry sees two more Dementors guarding the school gates. During the welcoming feast, Dumbledore informs the students of the Dementors' presence and warns them not to cross the creatures (PA5).

During the Defence Against the Dark Arts lesson in which they students have to face a Boggart, Harry Potter realises that his worst fear is a Dementor. Lupin, who thinks that the Boggart will turn into Lord Voldemort for Harry, never lets him confront the creature (PA7). Harry later asks him about his reasons and the misunderstanding is solved. Lupin compliments Harry, saying that the thing he fears most is fear itself (PA8).

During the Quidditch match of Gryffindor versus Hufflepuff, over a hundred Dementors leave their posts and enter the school grounds. Drawn by the ecstatic emotions of the crowd, they enter the Hogwarts Quidditch pitch. Their presence makes Harry Potter lose consciousness and drop from his broom. A furious Albus Dumbledore runs out onto the pitch and slows his fall before he conjures a Patronus that banishes the Dementors from the stadium. Hufflepuff SeekerCedric Diggory catches the Snitch at that moment and Hufflepuff wins the game, while Harry's Nimbus 2000 crashes into the Whomping Willow and is destroyed (PA9).

After his recovery from the fall, Harry asks Lupin to teach him the Patronus Charm (PA10). After Christmas, Harry practises the charm once a week on another Boggart that transforms into a Dementor for him (PA12). During the Quidditch match of Gryffindor versus Ravenclaw, Draco Malfoy, Vincent Crabbe, Gregory Goyle and Marcus Flint dress up as Dementors to scare Harry, who casts the Patronus Charm and conjures a corporeal Patronus for the first time (PA13).

Inside the Shrieking Shack, Severus Snape threatens and Lupin and Black over to the Dementors to be Kissed before is overpowered by the Trio. Sirius explains how he escaped the Dementors. Harry decides not to kill Pettigrew and send him to Azkaban and the Dementors instead (PA19). Outside, Sirius turns into a dog to keep Lupin, who has transformed into a werewolf, in check. He follows him and runs straight into a group of about a hundred Dementors. Overpowered by their impact, he turns back into a human. Harry and Hermione Granger come to his aid, but neither manages to produce a Patronus. The Dementors try to Kiss Harry, but before they can do so, Harry's future self, that has travelled into the past with the help of Hermione's Time-Turner, emerges and produces a Patronus that chases them away (PA20, PA21). The attack leaves all three unconcious and Sirius is captured by Snape, but before the Dememtors can Kiss him, Harry and Hermione help him escape. Worried about the fact that they tried to Kiss an innocent boy, Minister for MagicCornelius Fudge agrees to remove the Dementors from Hogwarts (PA21).

The year before the outbreak of the Second War

Harry speculates that one of the reasons Sirius goes south after his escape is that Dementors probably cannot survive in bright sunlight (GF2). After his return to England, Sirius tells the Trio that Bartemius Crouch, Sr. turned his own son over to the Dementors (GF27). In Dumbledore's Pensieve, Harry witnesses how the Dementors escort people accused of Death Eater activities, Barty Crouch, Jr. among them, into the Wizengamot (GF30).

The Second War

After his rebirthing, Lord Voldemort promises his Death Eaters that the Dementors will join them, as they are their natural allies (GF33).

Against Minerva McGonagall's protests, Cornelius Fudge brings a Dementor with him for his protection when he comes to interrogate Barty Crouch, Jr. When the Dementor catches sight of Crouch, it immediately Kisses him. Fudge therefore never hears Crouch's testimony and refuses to believe in Voldemort's return. Dumbledore asks him to withdraw the Dementors from Azkaban before they join Voldemort, but Fudge dismisses this advice as "preposterous" (GF36).

On the evening of August 2, 1995, Dolores Umbridge secretly orders a Dementor attack on Harry Potter in Little Whinging, Surrey to prevent him from returning to Hogwarts and spreading the news of Voldemort's return (OP1, OP32). Two Dementors attack Harry and his cousin Dudley Dursley in the alleyway between Magnolia Crescent and Wisteria Walk. The alleyway suddenly turns pitch-black and the temperature drops. Panicked, Dudley hits Harry and runs straight at one of the creatures, which tries to Kiss him. After a few failed attempts, Harry conjures a Patronus which chases off both Dementors. Light and warmth return. Dudley is traumatised (OP1)—he has seen himself as he really is for the first time (BLC). Arabella Figg, who has been warned by her cat, arrives and helps Harry to bring Dudley back home. Petunia and Vernon Dursley are enraged when they see the state of their son, who blaims Harry. Harry axplains that Dudley was the victim of a Dementor attack and Petunia betrays that she knows about the creatures—she once overheard Severus Snape telling her sister Lily about them (DH33). As a consequence of his illegal use of magic, Harry is summoned to a hearing at the Ministry of Magic on August 12, 1995 (OP2).

During the hearing, Arabella Figg appears as a witness and is able to convince the Wizengamot that there were indeed Dementors in Little Whinging. The court consequently decides that Harry's use of the Patronus Charm was justified and clears him of all charges (OP8).

On January 13, 1996, there is a mass breakout from Azkaban, indicating that the Dementors have joined Voldemort, whose return is still denied by the Ministry. It appears that the Dementors are out of Ministry control, as they are not even looking for the fugitives (OP25). The Ministry only confirms that the Dementors have changed sides when they admit Voldemort's return in June1995. The Daily Prophet is full of articles about how to repel Dementors in the following days (OP38). The Dementors leave Azkaban and start attacking people all over Britain. They send the country into a climate of unhappiness and despair and start breeding, causing a chilly mist in the middle of July. Fudge informs the Muggle Prime Minister of this and other unpleasant developments (HBP1). Word of more Dementor attacks spreads over the following months (HBP6, HBP11, HBP25). Shady merchants in Diagon Alley try to make a profit of the general fear by selling amulets against Dementors and other Dark creatures (HBP6). The sixth-years study Dementors in Defence Against the Dark Arts under Snape, and are asked to write a difficult essay about trhe best way to fight them (HBP21).

After Voldemort gains control of the Ministry, Dementors are used to guard the Muggle-born witches and wizards who areaccused of stealing magic. When the Trio enters the Ministry to steal Slytherin's locket from Dolores Umbridge, Harry sees several of the creatures watching over the witches and wizard awaiting trial in a corridor outside the courtrooms on level ten. He has to walk right through the rowd, and is anxious that the Dementors can feel him. He witnesses Umbridge threatening one of the accused who claims to be a half-blood with the Dementor's Kiss. When Mary Cattermole is called into a courtroom, he follows her inside. More Dementors are inside the courtroom in the corner farthest from the platform on which Umbridge, Yaxley and Hermione disguised as Mafalda Hopkirk sit. They are protected from the creatures' influence by Umbridge's Patronus. After Harry overpowers Yaxley and Umbridge, the Dementors try to Kiss Mary Cattermole, but Harry conjures a Patronus in time to save her. Hermione casts a second Patronus and they chase off the Dementors in the corridor and help the people awaiting trial escape (DH13).

When the Trio is camping in the woods, Harry runs into a group of Dementors while looking for food. He finds that he cannot conjure a Patronus while wearing the locket and has to flee (DH15).
The Trio also runs into a group of Dementors when they are hiding from Death Eaters in Hogsmeade. Harry casts a Patronus, which gives their presence away. Aberforth Dumbledore hides them in the Hog's Head and pretends that the Patronus the Death Eaters saw was his own goat Patronus. Aberforth also tells the Trio that Dementors guard all entrances to Hogwarts apart fron the tunnel that leads from the Hog's Head into the Room of Requirement (DH28, DH29).

During the Battle of Hogwarts, Dementors fight in Voldemort's army. The Trio meets a hundred them when they run towards the Forbidden Forest to save Hagrid. They are saved by Luna Lovegood, Ernie Macmillan and Seamus Finnigan's Patronuses (DH32). Later, when Harry goes into the forest alone to let Voldemort kill him, he knows he is not strong enough to fight the Dementors in his path on his own. He uses the Resurrection Stone to summon his parents, Remus and Sirius, and passes the creatures savely under their protection (DH34). The Dementors do ot affect him when he is carried back to the castle by Hagrid, pretending to be dead (DH36).

After Voldemort's defeat, the Ministry of Magic never uses Dementors again, neither in Azkaban nor in any other purposes (BLC).